PoE 2: Poison/Gas Cloud Explained

Poison Cloud, also known as Gas Cloud, is a Ground Effect created by several Skills in Path of Exile 2.

What is Poison Cloud?

Poison Cloud is a Ground Surface Effect that is created by Skills such as Gas Grenade, Gas Arrow and Decompose. Monsters in the Poison Cloud area are Poisoned every 2 seconds as though being Hit.

Tip: check out our full guide on the Poison Damaging Ailment here for Poison-specific mechanics!

Poison Cloud increases in Area of Effect over time, covering a larger area that grows from the initial target location, up to a maximum amount. For example Decompose gains 20% more Radius per second up to a maximum of 80% more after 4 seconds have passed.

Poisoned as though Hit

Both Gas Grenade and Gas Arrow have the modifier 'Does not Hit, but Poisons enemies as though Hitting them', while Decompose's modifier text reads differently but is functionally the same.

These modifiers will cause the Poison Cloud to inflict Poison as if it Hit a target, without actually making a Hit. This is an important part of the mechanics of Poison Cloud as it also affects other interactions, listed below.

Note: Poison Cloud does not Hit.

For Gas Arrow and Gas Grenade, the attack Damage multiplier is listed in the Poison Cloud section of the Skill. This is the Damage multiplier that is used to inflict Poison. By default, the Skill will take the multiplier and only use Physical and Chaos Hit Damage to calculate the inflicted Poison. You can use Plaguefinger to also include other Damage types in the Poison calculation.

Duration of Poison Cloud

The Duration of Poison Cloud is listed on the Skill gem and is scaled by modifiers to Skill Effect Duration. However, Poison Cloud Duration does not interact with the Duration of the inflicted Poisons. A Monster will be continuously Poisoned while remaining in the Poison Cloud area, so scaling Skill Effect Duration can be a good method against stationary targets. If a Monster is more mobile and often moves out of the Poison Cloud area, then scaling Poison Duration may be better to avoid downtime for Poison Damage.

Critical Hits

As of patch 0.3, Poison Cloud can now Critically Hit. This means the Poison inflicted by the Poison Cloud can be scaled with Critical Damage Bonus. When a Gas Grenade projectile is a Critical Hit, the resulting Poison Cloud will inflict Poisons scaled by Critical Damage Bonus every 2 seconds for its full Duration.

Accuracy

On the flipside, the Poison Cloud also cannot miss and will always inflict Poison if able. This will fully bypass the Hit check calculation, ignoring both your Accuracy Rating and the Monster's Evasion Rating.

Damage Gained as Extra

The Poisons inflicted by Poison Cloud are affected by modifiers that make you Gain Extra Damage, such as the Acolyte of Chayula's Purple Flames from Into the Breach. Extra Damage is calculated and applied to the inflicted Poison. By default, only Physical and Chaos Damage is accounted for in the Poison calculation, but you can use Plaguefinger to take advantage of Elemental Damage Gained as Extra modifiers.

Explosion

Gas Grenade, Gas Arrow and Decompose each have a built in mechanic that will cause the Poison Cloud to explode if it's exposed to any Ignited Enemies, Ignited Ground effects or Detonator Skills. This explosion will cause the Poison Cloud to be destroyed.

In the case of Gas Grenade and Gas Arrow, the explosion deals a Hit of Damage with 100% of Physical Damage converted to Fire. Decompose instead deals a Hit of Damage with base flat Fire Damage.

Ground Surface Effect

Poison Cloud is considered to be a Ground Surface Effect, and thus Skills like Gas Arrow can be Supported by Support Gems such as Persistent Ground III or Encroaching Ground.

Persistent Ground III is particularly notable here due to preventing the Poison Cloud from being destroyed by any means other than expiring normally.